Field of the Invention
The invention relates to a decoding device. In the fields of microelectronics, information technology and the like, it is often necessary to code and/or decode a number of addresses of electronic components by using hardware, in order to address memory elements, sensor elements (e.g. of image sensors, actuator elements or the like). This includes addressing their contents in order to read them, change their status, and so on.
Particularly in memory modules such as DRAMs (Dynamic Random Access Memories), it is common to select individual word lines from predecoded addresses in a word line decoder. To accomplish this, a final decoder is provided in conventional decoders for switchably transmitting a transmission signal, for instance a word line signal. The final decoder includes a first switching unit, with at least one field-controlled semiconductor switching device as the switch element. The conventional decoder also includes a transmission signal driver. This transmission signal driver is provided in the region of a transmission signal line for the purpose of generating a transmission signal and providing the transmission signal on the transmission signal line of the final decoder.
A drive line on which a driver signal is carried is usually utilized to select an area or range of so-called word lines and thus to put these in an activatable state. A range of components that are to be addressed corresponds to the range of word lines. In DRAMs this is known as a cell field of transistors, which are essentially put in an activatable or inactivatable state by a corresponding driver signal. The concrete selection of a word line and thus of an individual electronic component, for instance a specific transistor, is accomplished by way of preselected and correspondingly activated or inactivated word line drive lines. Only when the drive line belonging to a respective field-controlled semiconductor switching device and the appertaining word line drive line simultaneously carry a signal portion designating activation, for instance with the aid of a correspondingly selected electrical potential, is the corresponding switching unit or field-controlled semiconductor switching device actually put into an activated (i.e. conductive) state, as a consequence of which the transmission signal is then present on the word line in order to address a particular electronic component.
Due to the selection, which is realized by the interconnection or configuration of the decoder, of a specific electronic component from a plurality of components (e.g. n components), all field-controlled semiconductor switching devices of a group of activatable field-controlled semiconductor switching devices which correspond to the n components receive the driver signal designating an activation. But because only a single electronic component is actually intended to be selected, all the other field-controlled semiconductor switching devices, which do not correspond to selected electronic components of the group, receive a signal designating inactivation on their respective word line drive lines, i.e. on the transmission signal line.
As a result, potential differences exist at the respective field-controlled semiconductor switching devices in dependence upon the selection of the signals or potentials designating activation or inactivation, which potential differences allow a flow of various electric currents (zero current), or at least do not preclude such a current flow, though they do not enable a through-switching or activation of the respective field-controlled semiconductor switching device in the strict sense.
Consequently, in conventional decoders with corresponding final decoders including at least one field-controlled semiconductor switching device, signals or leakage currents are transmitted even in the inactive state of the field-controlled semiconductor switching device. Besides the corresponding energy losses, these leakage currents or zero currents also represent possible sources of error, because these types of signals can be superimposed throughout the network in an unpredictable fashion, ultimately causing disturbances of one form or another.
Although these additional leakage currents typically run at a low level and have therefore been treated as a problem of minor importance and have been neglected hitherto, it is of crucial importance to take these additional leakage currents into consideration, particularly in view of the long-term behavior of the corresponding decoders and furthermore in view of fundamentally novel transistor technologies whose lower threshold voltage behavior defies estimation by contemporary means.